Cardiovascular therapeutics: A new potential for anxiety treatment?

Repositioning pinacidil and its anticonvulsant and anxiolytic properties in murine models

Epilepsy, frequently comorbid with anxiety, is a prevalent neurological disorder. Available drugs often have side effects that hinder adherence, creating a need for new treatments. Potassium channel activators have emerged as promising candidates for treating both epilepsy and anxiety. This study aimed to evaluate the potential anticonvulsant and anxiolytic effects of pinacidil, an ATP-sensitive potassium channel activator used as antihypertensive, in rats. Our results indicate that pinacidil at 10 mg/kg (i.p.) fully protected animals from seizures induced by pentylenetetrazol (PTZ) and provided 85.7%, 100% and 100% protection against pilocarpine-induced seizures at 2.5, 5 and 10 mg/kg (i.p.), respectively. Although the 2.5 and 5 mg/kg (i.p) doses did not significantly protect the animals from PTZ-induced seizures, they did significantly increase the latency to the first seizure. Pinacidil also demonstrated mild anxiolytic activity, particularly at 10 mg/kg (i.p), evidenced by increased time spent in the open or illuminated areas of the Elevated Plus Maze (EPM) and Light-Dark Box (LDB) and increased exploratory activity in the Open Filed, EPM and LDB. Pinacidil did not affect locomotor performance, supporting its genuine anticonvulsant effects. This study holds significant medical and pharmaceutical value by characterizing pinacidil's anticonvulsant and anxiolytic effects and highlighting its potential for therapeutic repositioning.

Identification of novel genomic loci for anxiety symptoms and extensive genetic overlap with psychiatric disorders

AIMS

Anxiety disorders are prevalent and anxiety symptoms (ANX) co-occur with many psychiatric disorders. We aimed to identify genomic loci associated with ANX, characterize its genetic architecture, and genetic overlap with psychiatric disorders.

METHODS

We included a genome-wide association study of ANX (meta-analysis of UK Biobank and Million Veterans Program, n = 301,732), schizophrenia (SCZ), bipolar disorder (BIP), major depression (MD), attention-deficit/hyperactivity disorder (ADHD), and autism spectrum disorder (ASD), and validated the findings in the Norwegian Mother, Father, and Child Cohort (n = 95,841). We employed the bivariate causal mixture model and local analysis of covariant association to characterize the genetic architecture including overlap between the phenotypes. Conditional and conjunctional false discovery rate analyses were performed to boost the identification of loci associated with anxiety and shared with psychiatric disorders.

RESULTS

Anxiety was polygenic with 12.9k genetic variants and overlapped extensively with psychiatric disorders (4.1k-11.4k variants) with predominantly positive genetic correlations between anxiety and psychiatric disorders. We identified 119 novel loci for anxiety by conditioning on the psychiatric disorders, and loci shared between anxiety and MDn = 47 $$ \left(n=47\right) $$ , BIPn = 33 $$ \left(n=33\right) $$ , SCZn = 71 $$ \left(n=71\right) $$ , ADHDn = 20 $$ \left(n=20\right) $$ , and ASDn = 5 $$ \left(n=5\right) $$ . Genes annotated to anxiety loci exhibit enrichment for a broader range of biological pathways including cell adhesion and neurofibrillary tangle compared with genes annotated to the shared loci.

CONCLUSIONS

Anxiety is highly polygenic phenotype with extensive genetic overlap with psychiatric disorders, and we identified novel loci for anxiety implicating new molecular pathways. The shared genetic architecture may underlie the extensive cross-disorder comorbidity of anxiety, and the identified molecular underpinnings may lead to potential drug targets.

Effects of Hyperbaric Oxygen Therapy Combined with Music Therapy on Brain Function and Mental Health of Patients with Aneurismal Subarachnoid Hemorrhage: A Retrospective Study

BACKGROUND

Hyperbaric oxygen therapy (HBOT), which is widely used in clinical practice, is aimed at improving nerve function impairment after brain injury. Meanwhile, the effects of music therapy on brain function are unclear. This retrospective study was conducted to explore the application effect of HBOT combined with music therapy on patients suffering from aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

For this retrospective study, 130 patients with aSAH after HBOT were selected from our hospital from June 2021 to June 2022. The patients were divided into the observation (n = 70) and control (n = 60) groups based on whether they received music therapy. Comparisons were made on general demographic data, blood flow rate in median cerebral artery (MCA), cerebral vasospasm (CVS), National Institutes of Health Stroke Scale (NIHSS), activities of daily living (ADL) score, Self-Rating Depressive Scale (SDS), and Self-Rating Anxiety Scale (SAS) of patients.

RESULTS

Baseline data between the two groups showed no statistically significant difference (P > 0.05). After management, patients in the observation group presented significantly lower SAS and SDS scores (P < 0.05), lower blood flow rate in MCA, CVS and NIHSS scores (P < 0.05), and higher ADL scores than the control group (P < 0.05).

CONCLUSIONS

The combination of HBOT and music therapy can considerably improve cerebral neurological deficits, slow down cerebral arterial blood flow, promote the recovery of postoperative cerebral function in aSAH patients, and improve anxiety and depression and the patients' ADL.

Dorsal motor vagal neurons can elicit bradycardia and reduce anxiety-like behavior

Cardiovagal neurons (CVNs) innervate cardiac ganglia through the vagus nerve to control cardiac function. Although the cardioinhibitory role of CVNs in nucleus ambiguus (CVNNA) is well established, the nature and functionality of CVNs in dorsal motor nucleus of the vagus (CVNDMV) is less clear. We therefore aimed to characterize CVNDMV anatomically, physiologically, and functionally. Optogenetically activating cholinergic DMV neurons resulted in robust bradycardia through peripheral muscarinic (parasympathetic) and nicotinic (ganglionic) acetylcholine receptors, but not beta-1-adrenergic (sympathetic) receptors. Retrograde tracing from the cardiac fat pad labeled CVNNA and CVNDMV through the vagus nerve. Using whole-cell patch-clamp, CVNDMV demonstrated greater hyperexcitability and spontaneous action potential firing ex vivo despite similar resting membrane potentials, compared to CVNNA. Chemogenetically activating DMV also caused significant bradycardia with a correlated reduction in anxiety-like behavior. Thus, DMV contains uniquely hyperexcitable CVNs and is capable of cardioinhibition and robust anxiolysis.

A facile synthesis of 2-(4-((4-chlorophenyl)(hydroxy)methyl) phenoxy)-2-methylpropanoic acid: Metabolite of anti-hyperlipidemic drug Fenofibrate

Synthesis and characterization of drug metabolites has emerged as an important area of research in consideration to the significant contribution of studies on metabolites in drug research. The present work comprises synthesis of 2-(4-((4-chlorophenyl)(hydroxy)methyl) phenoxy)-2-methylpropanoic acid, a metabolite of anti-hyperlipidemic drug fenofibrate. The desired compound was prepared by two different synthetic routes. The ketone group of fenofibric acid was reduced using sodium borohydride in one route whereas the hydrolysis of isopropyl ester of the reduced fenofibrate was achieved by the mild alkaline hydrolysis in the other path. Both the ways of synthesis furnished the desired compound in excellent yield and purity. The new synthetic congener was characterized by spectroscopic methods.

Dorsal Motor Vagal Neurons Can Elicit Bradycardia and Reduce Anxiety-Like Behavior

Cardiovagal neurons (CVNs) innervate cardiac ganglia through the vagus nerve to control cardiac function. Although the cardioinhibitory role of CVNs in nucleus ambiguus (CVNNA) is well established, the nature and functionality of CVNs in dorsal motor nucleus of the vagus (CVNDMV) is less clear. We therefore aimed to characterize CVNDMV anatomically, physiologically, and functionally. Optogenetically activating cholinergic DMV neurons resulted in robust bradycardia through peripheral muscarinic (parasympathetic) and nicotinic (ganglionic) acetylcholine receptors, but not beta-1-adrenergic (sympathetic) receptors. Retrograde tracing from the cardiac fat pad labeled CVNNA and CVNDMV through the vagus nerve. Using whole cell patch clamp, CVNDMV demonstrated greater hyperexcitability and spontaneous action potential firing ex vivo despite similar resting membrane potentials, compared to CVNNA. Chemogenetically activating DMV also caused significant bradycardia with a correlated reduction in anxiety-like behavior. Thus, DMV contains uniquely hyperexcitable CVNs capable of cardioinhibition and robust anxiolysis.

Melatonin as a Potential Approach to Anxiety Treatment

Anxiety disorders are the most common mental diseases. Anxiety and the associated physical symptoms may disturb social and occupational life and increase the risk of somatic diseases. The pathophysiology of anxiety development is complex and involves alterations in stress hormone production, neurosignaling pathways or free radical production. The various manifestations of anxiety, its complex pathophysiological background and the side effects of available treatments underlie the quest for constantly seeking therapies for these conditions. Melatonin, an indolamine produced in the pineal gland and released into the blood on a nightly basis, has been demonstrated to exert anxiolytic action in animal experiments and different clinical conditions. This hormone influences a number of physiological actions either via specific melatonin receptors or by receptor-independent pleiotropic effects. The underlying pathomechanism of melatonin's benefit in anxiety may reside in its sympatholytic action, interaction with the renin-angiotensin and glucocorticoid systems, modulation of interneuronal signaling and its extraordinary antioxidant and radical scavenging nature. Of importance, the concentration of this indolamine is significantly higher in cerebrospinal fluid than in the blood. Thus, ensuring sufficient melatonin production by reducing light pollution, which suppresses melatonin levels, may represent an endogenous neuroprotective and anxiolytic treatment. Since melatonin is freely available, economically undemanding and has limited side effects, it may be considered an additional or alternative treatment for various conditions associated with anxiety.

Aminopeptidase Activities Interact Asymmetrically between Brain, Plasma and Systolic Blood Pressure in Hypertensive Rats Unilaterally Depleted of Dopamine

Brain dopamine, in relation to the limbic system, is involved in cognition and emotion. These functions are asymmetrically processed. Hypertension not only alters such functions but also their asymmetric brain pattern as well as their bilateral pattern of neurovisceral integration. The central and peripheral renin-angiotensin systems, particularly the aminopeptidases involved in its enzymatic cascade, play an important role in blood pressure control. In the present study, we report how these aminopeptidases from left and right cortico-limbic locations, plasma and systolic blood pressure interact among them in spontaneously hypertensive rats (SHR) unilaterally depleted of dopamine. The study comprises left and right sham and left and right lesioned (dopamine-depleted) rats as research groups. Results revealed important differences in the bilateral behavior comparing sham left versus sham right, lesioned left versus lesioned right, and sham versus lesioned animals. Results also suggest an important role for the asymmetrical functioning of the amygdala in cardiovascular control and an asymmetrical behavior in the interaction between the medial prefrontal cortex, hippocampus and amygdala with plasma, depending on the left or right depletion of dopamine. Compared with previous results of a similar study in Wistar-Kyoto (WKY) normotensive rats, the asymmetrical behaviors differ significantly between both WKY and SHR strains.

Sacubitril/Valsartan and Ivabradine Attenuate Left Ventricular Remodelling and Dysfunction in Spontaneously Hypertensive Rats: Different Interactions with the Renin-Angiotensin-Aldosterone System

This study investigated whether sacubitril/valsartan and ivabradine are able to prevent left ventricular (LV) fibrotic remodelling and dysfunction in a rat experimental model of spontaneous hypertension (spontaneously hypertensive rats, SHRs) and whether this potential protection is associated with RAAS alterations. Five groups of three-month-old male Wistar rats and SHRs were treated for six weeks as follows: untreated Wistar controls, Wistar plus sacubitril/valsartan, SHR, SHR plus sacubitril/valsartan, and SHR plus ivabradine. The SHRs developed a systolic blood pressure (SBP) increase, LV hypertrophy and fibrosis, and LV systolic and diastolic dysfunction. However, no changes in serum RAAS were observed in SHRs compared with the controls. Elevated SBP in SHRs was decreased by sacubitril/valsartan but not by ivabradine, and only sacubitril/valsartan attenuated LV hypertrophy. Both sacubitril/valsartan and ivabradine reduced LV collagen content and attenuated LV systolic and diastolic dysfunction. Sacubitril/valsartan increased the serum levels of angiotensin (Ang) II, Ang III, Ang IV, Ang 1-5, Ang 1-7, and aldosterone, while ivabradine did not affect the RAAS. We conclude that the SHR is a normal-to-low serum RAAS model of experimental hypertension. While the protection of the hypertensive heart in SHRs by sacubitril/valsartan may be related to an Ang II blockade and the protective Ang 1-7, the benefits of ivabradine were not associated with RAAS modulation.